This disclosure pertains to improved methods for utilizing 911 services and for implementing 911 dispatch protocols by accessing mobile phone sensors and applications. This disclosure also pertains to measurement of vital signs of a patient using mobile phone sensors and applications, including estimation of blood pressure without a traditional stethoscope and cuff.
The United States 9-1-1 System has its origin in 1958, when the Commission on Law Enforcement and Administration of Justice suggested replacing the patchwork of local police and fire numbers with a single national emergency number. The dispatcher is an important player in the 911 call center. This is the person who takes information about the emergency and arranges adequate resources to be sent to handle the situation. The process of gathering information by the dispatchers to access the emergency situation has been standardized into documents called Dispatch Protocols. The first use of the standardized protocols was recorded in Arizona in 1975.
Table 1 below shows the data for various categories of calls received in percentage terms. The table shows that Medical emergencies account for the largest number of calls, followed by fire and vehicle accidents. The Other category has the largest number of calls, but includes calls that cannot be classified into any category. This number also includes calls that were considered non-emergency
TABLE 1Category of 911 CallsType of EmergencyPercentage of TotalCallCallsMedical Emergency37Fire11Vehicle/Accidents10Chemical Hazards2Floods/Water1DamageElectricity/Wire1DownOther38
Emergency dispatch protocols were based in legacy telecom networks where only voice calls were used and the networks were all based on dedicated landlines over a call connection. Over the years the technology has developed to include wireless networks in which the call connections are no longer dedicated landlines, but based on packet networks. The bandwidth of the networks has also increased to a point where multimedia services are available to the general public.
Emergency response services are provided in most of the advanced countries. The role of the emergency dispatcher has its origins in the United States, but it has gained acceptance in all parts of the world. In the US, the Dispatch Protocols are called the Medical Priority Dispatch System (“MDPS”). It is a system that has about 37 cards and each card gives instructions to the dispatcher for a specific emergency type. A similar Dispatch Protocol is used by the state of New Jersey and is called the Emergency Medical Dispatch Guidecards. This protocol also has a set of cards that the dispatcher uses based on the type of emergency call. These cards act as a guide to the dispatcher. The success of the notion of Dispatch Protocols can be gauged from the fact that today many developed countries have developed their own protocols. The UK uses AMPDS, while France uses its own version of Dispatch Protocols, called SAMU.
The 9-1-1 system in the U.S. has evoked to include, for example, wireless 9-1-1 services in 1998. In 205, the FCC mandated that Voice over IP (“VoIP”) providers must offer 9-1-1 services also. Today, the architecture for Next Generation 9-1-1 (“NG911”) has been designed by the National Emergency Number Association (“NENA”). NENA first identified the need for an overhaul of the 911 system in the year 2000. The first document describing the future path was produced in 2001 and by the end of 2003 the standards development activity had started. NENA is developing several documents relating to the architecture. Some of the documents are already complete. For example the overall requirements document is defined in NENA i3 Technical Requirements Document, available publicly.
Each year, about 200 million emergency calls are placed in the US, with about one third originating from mobile phones. With the deployment of NG911, there is the potential to better utilize the capabilities of these mobile phones to improve 911 services and dispatch protocols.
Measurement of vital signs in a human is an arduous task when sudden dizziness or fainting occur during unexpected situations. These occurrences are the most common symptoms of low blood pressure. Blood pressure, the amount of force applied on the walls of the arteries when the blood is forced throughout the body, depends on factors such as the amount of blood in the body, the pumping rate of the heart, the flexibility of the arterial walls, and the resistance to blood flow due to the size of the arteries. The blood pressure of a human varies continuously due to physical activity, medication, anxiety, and emotions. The body has unique mechanisms to regulate a person's blood flow; whenever a person's blood pressure drops, the heart rate increases to pump more blood and the arterial walls contract to increase the blood pressure. Blood pressure is given by two numbers measured in millimeters of mercury (mmHg). The first number is the systolic pressure, which represents the amount of pressure applied in the arteries when the heart contracts. The second number is the diastolic pressure, which represents pressure on the arteries when the heart is at rest.
Blood pressure is typically measured in the upper arm with the person comfortably seated and the arm in level with the heart. The measurement apparatus is a mercury sphygmomanometer comprising a manometer, pressure cuff, bladder and a gauge to show the pressure value inside the cuff which is wrapped tightly around the upper arm about an inch from the elbow since the upper arm is closest to the heart and therefore errors due to upflow/downflow of blood are eliminated. When this setup is done, the cuff is inflated to a pressure of about 210 mmHg or usually 20 to 30 mmHg above the normal systolic pressure. The gradual reduction of inflation causes a turbulent flow of blood, creating a sound. The cuff pressure corresponding to the first sound produced is taken as the systolic pressure. The cuff pressure is further reduced and when the sounds due to blood flow cannot be heard with the stethoscope. That cuff pressure is taken as the diastolic pressure.
However, to check a person's blood pressure during unexpected situations, there is a need for a portable, convenient device or apparatus. Despite the availability of digital wrist and arm blood-pressure meters, most people do not carry these devices during their daily commute to work place, gymnasiums, recreating facilities, or other places.
However, smartphones today have become increasingly popular with the general public for their diverse functionalities such as navigation, social networking, and multimedia facilities. These phones are equipped with high end processors, high resolution cameras, and built-in sensors such as accelerometer, orientation sensor and light-sensor. It is estimated that 25.3% of US adults use smart phones in their daily lives. Being prevalent in people's lives, it is highly desirable to utilize these mobile phones to measure vital signs of a human.